<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org"
      th:replace="~{/test/layout1}">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div th:fragment="content">
        欢迎来到页面a
    </div>
</body>
</html>